The activity concentration of natural (U-238, Th-232, and K-40) and artificial (Cs-137) radionuclides was determined in 50 samples (obtained from the same station) from various species of mushrooms and soil collected from the Middle Black Sea Region (Turkey). The activities of U-238, Th-232, K-40, and Cs-137 were found as 84 +/- 16, 45 +/- 14, 570 +/- 28, and 64 +/- 6Bqkg(-1) (dry weight), respectively, in the mushroom samples and as 51 +/- 6, 41 +/- 6, 201 +/- 11, and 44 +/- 4Bqkg(-1), respectively, in the soil samples for the entire area of study. The results of all radionuclide activity measurements, except those of U-238 and Th-232 in the mushroom samples, are consistent with previous studies. In the soil samples, the mean values of U-238 and Th-232 are above the world mean, and the activity mean of K-40 is below the world mean. Finally, the activity estimation was made with both the soil and mushroom samples for unmeasured points within the study area by using the ordinary kriging method. Radiological distribution maps were generated.